Propylene resin composition and molded article

Abstract

To provide a polypropylene-based resin material having high rigidity and a low linear expansion coefficient.SOLUTION: There is provide a polypropylene-based resin composition which comprises 30 to 80 pts.mass of a propylene-based polymer (A) satisfying the requirements (i) to (iii), 10 to 50 pts.mass of a propylene-based polymer (B) satisfying the requirement (iv), 1 to 20 pts.mass of an inorganic filler (D) and optionally 0 to 5 pts.mass of an elastomer (C) (the total amount of (A) to (D) is 100 pts.mass). (i) The composition contains 5 to 25 pts.wt. of a propylene-based polymer (A1) having an intrinsic viscosity [η] (at 135°C in a tetralin solvent) of 7 to 12 dl / g. (ii) The melt flow rate (at 230°C under a load of 2.16 kg) is 1 to 20 g / 10 min. (iii) The mesopentad fraction is 97.0 to 100%. (iv) The intrinsic viscosity [η] (at 135°C in a tetralin solvent) is 0.15 to 0.28 dl / g.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a propylene-based resin composition and a molded article. [Background technology]

[0002] Molded articles obtained by injection molding polypropylene resin materials have excellent mechanical properties and moldability, and are relatively cost-effective compared to other materials, leading to their increasing use in various fields such as automotive parts and home appliance parts (for example, Patent Document 1).

[0003] On the other hand, polypropylene molded products generally have poor dimensional stability, making them difficult to apply to components that experience large temperature fluctuations once assembled. As a result, their high design potential and excellent economic benefits have not been fully realized.

[0004] As a technology to solve such problems, for example, Patent Document 2 discloses a polypropylene resin composition containing a polypropylene resin base material, a base component consisting of a copolymer of ethylene and one or more olefins selected from α-olefins having 4 to 10 carbon atoms, and an olefin-based (co)polymer having a number average molecular weight of 10,000 or less. Patent Document 3 discloses a polypropylene resin composition containing a propylene polymer, a propylene homopolymer, an ethylene-α-olefin copolymer, and an inorganic filler. Patent Document 4 discloses a propylene resin composition containing a propylene polymer, an olefin polymer, and an inorganic filler. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2021 / 025141 [Patent Document 2] Japanese Patent Publication No. 2014-214202 [Patent Document 3] Japanese Patent Publication No. 2017-88742 [Patent Document 4] Japanese Patent Publication No. 2017-222850 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, conventional polypropylene resin materials had room for further improvement in terms of forming molded articles with high rigidity and a low coefficient of thermal expansion. In view of the above-mentioned prior art, the present invention aims to provide a molded article with high rigidity and a low coefficient of thermal expansion, and a propylene-based resin composition capable of forming such a molded article. [Means for solving the problem]

[0007] The present invention relates, for example, to the following [1] to [5]. [1] 30 to 80 parts by mass of a propylene polymer (A) that satisfies the following requirements (i) to (iii), 10 to 50 parts by mass of a propylene polymer (B) that satisfies the following requirement (iv), and Inorganic filler (D) in 1 to 20 parts by mass, and Optionally, 0 to 5 parts by mass of elastomer (C) (where the total amount of (A), (B), (C), and (D) is 100 parts by mass). A propylene-based resin composition containing this resin. (i) Contains 5 to 25 parts by weight of a propylene polymer (A1) having an intrinsic viscosity [η] of 7 to 12 dl / g as measured at 135°C in a tetralin solvent. (ii) The melt flow rate (MFR) measured at 230°C and a 2.16 kg load is 1 to 20 g / 10 min. (iii) 13 The mesopentade fraction (mmmm) determined by 13C-NMR is 97.0–100%. (iv) The intrinsic viscosity [η] measured at 135°C in tetralin solvent is 0.15–0.28 dl / g. [2] The 13 propylene resin composition according to [1] above, wherein the meso pentad fraction (mmmm) determined by C-NMR of the propylene-based polymer (B) is 90.0 to 100%. [3] The propylene resin composition according to [1] or [2] above, wherein the proportion of the component eluted at a temperature of -20°C or lower by the temperature rising elution fractionation measurement method (TREF) of the propylene-based polymer (B) is 3.5% by mass or less. [4] The propylene resin composition according to any one of [1] to [3] above, containing 0.01 to 1 part by mass of a nucleating agent. [5] A molded article made of the propylene resin composition according to any one of [1] to [4] above.

Advantages of the Invention

[0008] According to the propylene resin composition of the present invention, a molded article having high rigidity and a small linear expansion coefficient can be produced. Further, the molded article according to the present invention has high rigidity and a small linear expansion coefficient.

Modes for Carrying Out the Invention

[0009] Hereinafter, the present invention will be described in more detail. Details of the measurement conditions for each physical property described below are described in the Examples section. The intrinsic viscosity [η] measured in a tetralin solvent at 135°C is also simply referred to as "intrinsic viscosity [η]". Further, each component described below may be used singly or in combination of two or more unless otherwise specified.

[0010] [Propylene resin composition] The propylene resin composition according to the present invention (hereinafter, also simply referred to as "composition") contains a propylene-based polymer (A), a propylene-based polymer (B), and an inorganic filler (D), which will be described below respectively.

[0011] <Propylene-based polymer (A)> The propylene-based polymer (A) satisfies the following requirements (i) to (iii). Requirement (i): The propylene polymer (A) contains a propylene polymer component (A1) whose intrinsic viscosity [η], measured at 135°C in a tetralin solvent, is in the range of 7 to 12 dl / g. This intrinsic viscosity [η] value can be adjusted, for example, by the hydrogen concentration in the polymerization system in the method for producing the propylene polymer component (A1) in the method for producing the propylene polymer (A) described later.

[0012] The intrinsic viscosity [η] of the propylene polymer component (A1) is preferably in the range of 10 to 12 dl / g, more preferably 10.5 to 12 dl / g. When the intrinsic viscosity [η] of the propylene polymer component (A1) is within this range, molded articles with excellent rigidity and appearance tend to be obtained.

[0013] Requirement (ii): The melt flow rate (MFR) of the propylene polymer (A), measured at 230°C and a 2.16 kg load, is 1 to 20 g / 10 min, preferably 2 to 18 g / 10 min, and more preferably 4 to 15 g / 10 min.

[0014] This melt flow rate can be adjusted, for example, by controlling the hydrogen concentration in the polymerization system in the method for producing the propylene polymer (A) described later. When the melt flow rate of the propylene polymer (A) is within the above range, the propylene resin composition exhibits an excellent balance between rigidity and impact resistance.

[0015] Requirement (iii): Propylene polymer (A) 13 The mesopentade fraction (mmmm) determined by 13C-NMR is 97.0-100%, preferably 97.3-100%, and more preferably 97.5-100%.

[0016] The mesopentad fraction represents the proportion of quintuple isotactic structures in a molecular chain, and is the fraction of propylene units at the center of a chain that has a mesostructure consisting of five consecutive propylene units.

[0017] The value of this mesopentade fraction can be adjusted, for example, by a catalyst for producing propylene polymers in the method for producing propylene polymers (A) described later. When the mesopentad fraction (mmmm) is within the above range, the rigidity of the propylene-based resin composition is excellent. On the other hand, when the mesopentad fraction (mmmm) falls below the above range, the rigidity of the propylene-based resin composition decreases.

[0018] The propylene polymer (A) has a melting point (Tm) measured by differential scanning calorimeter (DSC) that is preferably 150°C or higher, more preferably 155-170°C, and even more preferably 157-170°C. A Tm of Tm above the lower limit is preferable from the viewpoint of heat resistance. The melting point (Tm) is defined as the temperature at the peak of the endothermic peak in the third step under the following measurement conditions.

[0019] (Measurement conditions) Step 1: Heat the temperature to 230°C at a rate of 10°C / minute and hold for 10 minutes. Step 2: Cool the temperature down to 30°C at a rate of 10°C / minute. Step 3: Heat the temperature to 230°C at a rate of 10°C / minute.

[0020] One or more types of propylene polymers (A) can be used. The propylene polymer (A) is preferably a propylene polymer mixture containing a propylene polymer component (A2) in addition to a propylene polymer component (A1).

[0021] The propylene polymer component (A1) is a homopolymer of propylene. Examples of the propylene-based polymer component (A2) include propylene homopolymers and copolymers of propylene and α-olefins having 2 to 20 carbon atoms (excluding propylene). Examples of α-olefins having 2 to 20 carbon atoms include ethylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. Ethylene is preferred among these α-olefins. One or more of the α-olefins can be used.

[0022] In a copolymer of propylene and an α-olefin having 2 to 20 carbon atoms, the content of constituent units derived from propylene is usually greater than 90 mol% and less than 100 mol%, preferably 93 to 99 mol%, relative to the total number of constituent units derived from propylene and the α-olefin having 2 to 20 carbon atoms, and the content of constituent units derived from the α-olefin having 2 to 20 carbon atoms (excluding propylene) is usually greater than 0 mol% and less than 10 mol%, preferably 1 to 7 mol%. The above content ratios are, 13 It can be measured by 13C-NMR. In one embodiment, the copolymer is a random copolymer.

[0023] The proportion of propylene polymer component (A1) in the propylene polymer (A), which is a propylene polymer mixture, is preferably 5 to 40% by mass, more preferably 7 to 35% by mass, and even more preferably 10 to 30% by mass (provided that the total of propylene polymer component (A1) and propylene polymer component (A2) is 100% by mass).

[0024] ≪Method for producing propylene polymer (A)≫ The propylene polymer (A) can be produced by known methods such as slurry polymerization and bulk polymerization. Furthermore, it is preferable to use a catalyst for propylene polymer production, as described later.

[0025] When the propylene polymer (A) contains only the propylene polymer component (A1) as a polymer component, for example, the propylene polymer (A) can be produced by bulk polymerization of the raw material monomers in the absence of hydrogen, with a polymerization temperature preferably 20 to 80°C, more preferably 40 to 70°C, and a polymerization pressure generally at atmospheric pressure to 9.8 MPa, preferably 0.2 to 4.9 MPa.

[0026] If the propylene polymer (A) contains a propylene polymer component (A2), a propylene polymer (A) containing propylene polymer (A1) and propylene polymer (A2) can be obtained, for example, by multi-stage polymerization of two or more stages.

[0027] In the step of producing the propylene polymer component (A1), preferably, in the absence of hydrogen, the raw material monomers are bulk polymerized at a polymerization temperature of preferably 20 to 80°C, more preferably 40 to 75°C, and a polymerization pressure of generally atmospheric pressure to 9.8 MPa, preferably 0.2 to 4.9 MPa, to produce the propylene polymer component (A1).

[0028] In the step of producing the propylene polymer component (A2), the raw material monomers are bulk polymerized under conditions where hydrogen is present as a molecular weight modifier, preferably with a polymerization temperature of 20 to 80°C, more preferably 40 to 75°C, and a polymerization pressure of generally atmospheric pressure to 9.8 MPa, preferably 0.2 to 4.9 MPa, to produce the propylene polymer component (A2).

[0029] A preferred method for producing the propylene polymer (A) is, for example, a method in which propylene is polymerized by two or more multi-stage polymerization in the presence of a polypropylene production catalyst, which will be described later, either alone or in combination with other monomers.

[0030] Specifically, one method involves polymerizing propylene in the first stage of polymerization in substantially the absence of hydrogen to produce a propylene polymer component (A1) with [η] of 7 to 12 dl / g, and then producing a propylene polymer component (A2) with [η] of less than 7 dl / g in the second and subsequent stages of polymerization. The method for adjusting the intrinsic viscosity [η] of the propylene polymer produced in the second and subsequent stages is not particularly limited, but a method using hydrogen as a molecular weight modifier is preferred.

[0031] Regarding the production sequence (polymerization sequence) of the propylene polymer component (A1) and the propylene polymer component (A2), it is preferable to first produce a relatively high molecular weight propylene polymer component (A1) in the first stage in substantially the absence of hydrogen, and then produce a relatively low molecular weight propylene polymer component (A2) in the second stage and beyond, for example, in the presence of hydrogen. The production sequence can also be reversed, but in order to produce a relatively low molecular weight propylene polymer component (A2) in the first stage and then produce a relatively high molecular weight propylene polymer component (A1) in the second stage and beyond, it is necessary to remove as much as possible of molecular weight adjusting agents such as hydrogen contained in the reaction product of the first stage before the start of polymerization in the second stage and beyond. This makes the polymerization apparatus complex, and the intrinsic viscosity [η] of the second stage and beyond does not increase easily.

[0032] In multi-stage polymerization, each stage of polymerization can be carried out continuously or in batches, but batch polymerization is preferred. This is because when the propylene polymer mixture is produced by a continuous multi-stage polymerization method, compositional unevenness occurs between polymerized particles due to the residence time distribution, which can increase the number of fish eyes. By polymerizing in batches, a propylene polymer mixture with fewer fish eyes can be obtained.

[0033] ≪Catalyst for Propylene Polymer Production≫ A catalyst for the production of propylene polymers (hereinafter also simply referred to as "catalyst") that can be used to produce propylene polymers (A) can be formed from, for example, a solid catalyst component having magnesium, titanium, and halogen as essential components, an organometallic compound catalyst component such as an organoaluminum compound, and an electron-donating compound catalyst component such as an organosilicon compound. Typical catalyst components that can be used include the following.

[0034] (Solid catalyst component) As the support constituting the solid catalyst component, a support obtained from metallic magnesium, an alcohol, and a halogen and / or halogen-containing compound is preferred.

[0035] As metallic magnesium, magnesium in granular, ribbon, or powder form can be used. Furthermore, it is preferable that the metallic magnesium does not have a coating of magnesium oxide or the like on its surface.

[0036] As the alcohol, it is preferable to use a lower alcohol having 1 to 6 carbon atoms, and in particular, using ethanol yields a support that significantly improves the catalytic performance. The amount of alcohol used is preferably 2 to 100 moles, more preferably 5 to 50 moles, per mole of metallic magnesium. One or more types of alcohol can be used.

[0037] Preferred halogens include chlorine, bromine, and iodine, with iodine being preferred. Preferred halogen-containing compounds are MgCl2 and MgI2. The amount of halogen or halogen-containing compound used is typically 0.0001 grams or more, preferably 0.0005 grams or more, and more preferably 0.001 grams or more, per gram of metallic magnesium. One or more halogens and halogen-containing compounds can be used.

[0038] One method for obtaining a support by reacting metallic magnesium, an alcohol, and a halogen and / or halogen-containing compound is to react the metallic magnesium, the alcohol, and the halogen and / or halogen-containing compound under reflux (e.g., at about 79°C) until no hydrogen gas is observed (usually 20 to 30 hours). The reaction is preferably carried out under an inert gas atmosphere such as nitrogen gas or argon gas.

[0039] When the obtained support is used in the synthesis of solid catalyst components, it may be used in a dried state, or it may be used after filtration and washing with an inert solvent such as heptane. The resulting carrier is nearly granular, and has a sharp particle size distribution. Furthermore, even when considering individual particles, the variation in particle shape is very small. In this case, it is preferable that the sphericity (S) represented by the following formula (I) is less than 1.60, particularly less than 1.40, and the particle size distribution index (P) represented by the following formula (II) is less than 5.0, particularly less than 4.0.

[0040] S=(E1 / E2) 2 ...(I) In equation (I), E1 represents the contour length of the particle projection, and E2 represents the circumference of a circle equal to the projected area of ​​the particle.

[0041] P = D90 / D10...(II) In equation (II), D90 represents the particle size corresponding to a mass accumulation fraction of 90%. That is, it indicates that the sum of the masses of particles smaller than the particle size represented by D90 accounts for 90% of the total sum of the masses of all particles. D10 represents the particle size corresponding to a mass accumulation fraction of 10%.

[0042] The solid catalyst component is usually obtained by contacting the above-mentioned support with at least a titanium compound. Contact with the titanium compound may be carried out in multiple steps. Examples of titanium compounds include titanium compounds represented by general formula (III).

[0043] TiX 1 n (OR 1 )4-n ···(III) In formula (III), X 1 is a halogen atom, particularly preferably a chlorine atom, R 1 is a hydrocarbon group having 1 to 10 carbon atoms, preferably a linear or branched alkyl group. When there are a plurality of Rs 1 they may be the same or different from each other, and n is an integer of 0 to 4.

[0044] Specific examples of the titanium compound include Ti(O-i-C3H7)4, Ti(O-C4H9)4, TiCl(O-C2H5)3, TiCl(O-i-C3H7)3, TiCl(O-C4H9)3, TiCl2(O-C4H9)2, TiCl2(O-i-C3H7)2, and TiCl4, with TiCl4 being preferred.

[0045] One or more titanium compounds can be used. The solid catalyst component is usually obtained by further contacting the above carrier with an electron-donating compound. Examples of the electron-donating compound include di-n-butyl phthalate. One or more electron-donating compounds can be used.

[0046] When contacting the above carrier with the titanium compound and the electron-donating compound, a halogen-containing silicon compound such as silicon tetrachloride can be contacted. One or more halogen-containing silicon compounds can be used.

[0047] Solid catalyst components can be prepared by known methods. For example, an inert hydrocarbon such as pentane, hexane, peptane, or octane is used as a solvent, and the above-mentioned carrier, electron-donating compound, and halogen-containing silicon compound are added to the solvent, and the titanium compound is added while stirring. Typically, 0.01 to 10 moles, preferably 0.05 to 5 moles, of the electron-donating compound are added per mole of carrier in terms of magnesium atoms, and 1 to 50 moles, preferably 2 to 20 moles, of the titanium compound are added per mole of carrier in terms of magnesium atoms, and the catalytic reaction is carried out at 0 to 200°C for 5 minutes to 10 hours, preferably at 30 to 150°C for 30 minutes to 5 hours. After the reaction is complete, it is preferable to wash the generated solid catalyst components with an inert hydrocarbon such as n-hexane or n-heptane.

[0048] Furthermore, the solid catalyst component may be a component obtained by contacting a liquid magnesium compound and a liquid titanium compound in the presence of an electron-donating compound. Contact with the liquid titanium compound may be carried out in multiple steps.

[0049] Liquid magnesium compounds are obtained, for example, by contacting a known magnesium compound and an alcohol, preferably in the presence of a liquid hydrocarbon medium, to make them liquid. Examples of magnesium compounds include magnesium halides such as magnesium chloride and magnesium bromide. Examples of alcohols include aliphatic alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and 2-ethylhexyl alcohol. Examples of liquid hydrocarbon mediums include hydrocarbon compounds such as heptane, octane, and decane. The amount of alcohol used when preparing a liquid magnesium compound is usually 1.0 to 25 moles, preferably 1.5 to 10 moles, per mole of magnesium compound. One or more liquid magnesium compounds can be used.

[0050] Examples of liquid titanium compounds include the titanium compounds represented by the general formula (III) mentioned above. The amount of liquid titanium compound used per mole of magnesium atoms (Mg) contained in the liquid magnesium compound is usually 0.1 to 1000 moles, preferably 1 to 200 moles. One or more types of liquid titanium compounds can be used.

[0051] Examples of electron-donating compounds include dicarboxylic acid ester compounds such as phthalates, acid anhydrides such as phthalic anhydride, organosilicon compounds such as dicyclopentyl dimethoxysilane, dicyclohexyl dimethoxysilane, and cyclohexylmethyl dimethoxysilane, polyethers, acid halides, acid amides, nitriles, and organic acid esters. The amount of electron-donating compound used per mole of magnesium atoms (Mg) in the liquid magnesium compound is usually 0.01 to 5 moles, preferably 0.1 to 1 mole. One or more electron-donating compounds can be used. The temperature at which contact occurs is typically -70 to 200°C, preferably 10 to 150°C.

[0052] (organometallic compound catalyst component) Among the catalyst components, organoaluminum compounds are preferred as organometallic compound catalyst components. Examples of organoaluminum compounds include those represented by general formula (IV).

[0053] AlR 2 n X 2 3-n ...(IV) In formula (IV), R 2 X is an alkyl group, cycloalkyl group, or aryl group having 1 to 10 carbon atoms. 2 n is a halogen atom or an alkoxy group, preferably a chlorine atom or a bromine atom, and n is an integer from 1 to 3.

[0054] Examples of organoaluminum compounds include trialkylaluminum compounds such as trimethylaluminum, triethylaluminum, and triisobutylaluminum, as well as diethylaluminum monolide, diisobutylaluminum monolide, diethylaluminum monoethoxide, and ethylaluminum sesquichloride.

[0055] One or more organoaluminum compounds may be used. The amount of organometallic compound catalyst component used is typically 0.01 to 20 moles, preferably 0.05 to 10 moles, per mole of titanium atoms in the solid catalyst component.

[0056] (Electron-donating compound catalyst component) Among the catalyst components, organosilicon compounds are preferred as the electron-donating compound component for the polymerization system. Examples of organosilicon compounds include dicyclopentyl dimethoxysilane, cyclohexylmethyl dimethoxysilane, diethylaminotriethoxysilane, diisopropyl dimethoxysilane, and cyclohexyl isobutyl dimethoxysilane.

[0057] One or more organosilicon compounds may be used. The amount of electron-donating compound component used is typically 0.01 to 20 moles, preferably 0.1 to 5 moles, per mole of titanium atoms in the solid catalyst component.

[0058] (Pre-processing) It is preferable to use the above-mentioned solid catalyst components in polymerization after pretreatment such as prepolymerization. For example, an inert hydrocarbon such as pentane, hexane, peptane, or octane is used as the solvent, and the above-mentioned solid catalyst components, organometallic compound catalyst components, and optionally electron-donating compound components are added to the solvent, and propylene is supplied while stirring to allow the reaction to proceed. It is preferable to supply the propylene under a partial pressure of propylene higher than atmospheric pressure and pretreat it at 0 to 100°C for 0.1 to 24 hours. After the reaction is complete, it is preferable to wash the pretreated material with an inert hydrocarbon such as n-hexane or n-heptane.

[0059] <Propylene-based polymer (B)> The propylene polymer (B) has an intrinsic viscosity [η] measured at 135°C in a tetralin solvent in the range of 0.15 to 0.28 dl / g, preferably in the range of 0.19 to 0.25 dl / g. When the intrinsic viscosity [η] of the propylene polymer (B) is below the upper limit, the rigidity of the propylene resin composition is significantly improved and it exhibits excellent low linear expansion properties, and when the intrinsic viscosity [η] is above the lower limit, the toughness of the propylene resin composition can be maintained.

[0060] The propylene polymer (B) preferably has a component content of 3.5% by mass or less, more preferably 3.2% by mass or less, and even more preferably 3.0% by mass or less, in the temperature-reduced elution fractionation method (TREF) under the measurement conditions used in the examples described later, when measured at temperatures of -20°C or below. The lower limit may be, for example, 0.1% by mass. Here, the total amount of components eluted at measurement temperatures of -20 to 130°C in TREF is defined as 100% by mass. When the percentage of eluted components is within the above range, the rigidity and heat resistance of the resulting molded article tend to improve.

[0061] Propylene polymer (B) is 13The mesopentade fraction (mmmm) determined by 13C-NMR is preferably 90.0 to 100%, more preferably 96.0 to 100%, and even more preferably 97.0 to 100%. In one embodiment, the upper limit of mmmm may be 99.9%, 99.5%, or 99.0%. A mmmm value greater than or equal to the lower limit is preferable from the viewpoint of heat resistance.

[0062] Examples of propylene-based polymers (B) include propylene homopolymers and copolymers of propylene and α-olefins having 2 to 20 carbon atoms (excluding propylene). Examples of α-olefins having 2 to 20 carbon atoms include ethylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.

[0063] Among these polymers, propylene homopolymer, propylene / ethylene copolymer, propylene / 1-butene copolymer, propylene / 1-hexene copolymer, propylene / 4-methyl-1-pentene copolymer, propylene / 1-octene copolymer, propylene / ethylene / 1-butene copolymer, propylene / ethylene / 1-hexene copolymer, propylene / ethylene / 4-methyl-1-pentene copolymer, and propylene / ethylene / 1-octene copolymer are preferred, with propylene homopolymer being particularly preferred.

[0064] In a copolymer of propylene and an α-olefin having 2 to 20 carbon atoms, the content of constituent units derived from propylene is usually 98 mol% or more and less than 100 mol%, preferably 99 mol% or more and less than 100 mol%, relative to the total number of constituent units derived from propylene and the α-olefin having 2 to 20 carbon atoms, and the content of constituent units derived from the α-olefin having 2 to 20 carbon atoms (excluding propylene) is usually greater than 0 mol% and 2 mol% or less, preferably greater than 0 mol% and 1 mol% or less. The above content ratios are, 13It can be measured by 13C-NMR.

[0065] ≪Method for producing propylene polymer (B)≫ The propylene polymer (B) is preferably produced by homopolymerizing propylene in the presence of a metallocene catalyst, or by copolymerizing propylene with another monomer.

[0066] The propylene polymer (B) can be produced, for example, by the method described in paragraphs

[0064] to

[0125] of International Publication No. 2021 / 025141. The propylene polymer (A) and the propylene polymer (B) may each contain at least one constituent unit derived from a biomass-derived monomer (propylene). The monomers of the same type that constitute the polymer may consist only of biomass-derived monomers, only of fossil fuel-derived monomers, or may contain both biomass-derived monomers and fossil fuel-derived monomers. Biomass-derived monomers are monomers made from any renewable natural raw materials and their residues, including fungi, yeasts, algae, and bacteria, which are plant-derived or animal-derived, and contain 1 × 10⁻¹⁶ carbon isotopes. -12 It contains a certain proportion, and the biomass carbon concentration (pMC) measured according to ASTM D 6866 is approximately 100 pMC. Biomass-derived monomers (propylene) can be obtained, for example, by conventionally known methods.

[0067] It is preferable from the viewpoint of reducing environmental impact that the propylene polymer (A) or the propylene polymer (B) contains constituent units derived from biomass-derived monomers. If the polymer production conditions such as polymerization catalyst and polymerization temperature are the same, even if the raw material olefin is a propylene polymer containing biomass-derived olefins, the 14C isotope is 1 × 10⁻¹⁶. -12 Aside from containing it in a certain proportion, its molecular structure is equivalent to that of propylene polymers composed of fossil fuel-derived monomers. Therefore, its performance is considered to be the same.

[0068] <Inorganic filler (D)> The propylene resin composition according to the present invention contains an inorganic filler (D). Examples of inorganic fillers (D) include talc, clay, mica, calcium carbonate, magnesium hydroxide, ammonium phosphate, silicates, carbonates, carbon black; and inorganic fibers such as magnesium sulfate fibers, glass fibers, and carbon fibers.

[0069] Among these, talc, magnesium sulfate fibers, glass fibers, and carbon fibers are preferred in terms of superior rigidity, and talc is more preferred in terms of superior rigidity and low warping deformation.

[0070] <Elastomer (C)> The propylene-based resin composition according to the present invention may optionally contain an elastomer (C).

[0071] While elastomer (C) is not particularly limited, olefin-based elastomers are preferred due to their good compatibility with the propylene-based polymers (A) and (B) described above. Examples of olefin-based elastomers include ethylene-propylene copolymer rubber (EPR), ethylene-butene copolymer rubber (EBR), ethylene-octene copolymer rubber (EOR), styrene-butadiene copolymer rubber (SBR), and polystyrene-ethylene / butene-polystyrene block copolymer (SEBS).

[0072] <Optional ingredients> The compositions of the present invention may contain other components besides those described above, to the extent that they do not impair the effects of the present invention, such as resins, rubbers, nucleating agents, heat-resistant stabilizers, weather-resistant stabilizers, antistatic agents, anti-slip agents, anti-blocking agents, anti-fogging agents, lubricants, pigments, dyes, plasticizers, anti-aging agents, hydrochloric acid absorbers, and antioxidants.

[0073] Examples of nucleating agents include organic nucleating agents such as phosphate-based nucleating agents (organophosphate metal salts), sorbitol-based nucleating agents, metal salts of aromatic carboxylic acids, metal salts of aliphatic carboxylic acids, and rosin-based compounds; and inorganic nucleating agents such as inorganic compounds.

[0074] Examples of commercially available nuclear agents include the phosphate-based nuclear agent "ADEKA Stab NA-11" (manufactured by ADEKA Corporation), the sorbitol-based nuclear agent "Milad NX8000" (manufactured by Milliken Corporation), the nuclear agent "Hyperform HPN-20E" (manufactured by Milliken Corporation), which consists of a metal salt of an aliphatic carboxylic acid, and the nuclear agent "Pine Crystal KM1610" (manufactured by Arakawa Chemical Co., Ltd.), which consists of a rosin-based compound.

[0075] When the composition according to the present invention contains a nucleating agent, the proportion of the nucleating agent in the composition is preferably 0.01 to 1 part by mass, more preferably 0.02 to 0.8 parts by mass, and even more preferably 0.03 to 0.5 parts by mass, in one embodiment. However, the total amount of the propylene polymer (A), propylene polymer (B), elastomer (C), and inorganic filler (D) is 100 parts by mass.

[0076] <Content of each ingredient> The content of the propylene polymer (A) in the composition according to the present invention is 30 to 80 parts by mass, preferably 32 to 75 parts by mass, more preferably 35 to 70 parts by mass. The content of the propylene polymer (B) in the composition according to the present invention is 10 to 50 parts by mass, preferably 15 to 50 parts by mass, more preferably 20 to 50 parts by mass. The elastomer (C) content in the composition according to the present invention is 0 to 5 parts by mass, preferably 0 to 3 parts by mass. The inorganic filler (D) content in the composition according to the present invention is 1 to 20 parts by mass, preferably 5 to 20 parts by mass, and more preferably 10 to 20 parts by mass.

[0077] In all proportions, the total amount of propylene polymer (A), propylene polymer (B), elastomer (C), and inorganic filler (D) is 100 parts by mass. If the content of the propylene polymer (A) is less than the lower limit, the resulting molded article tends to have insufficient rigidity, and if it is more than the upper limit, the resulting molded article tends to have a poor appearance (e.g., the occurrence of blemishes).

[0078] If the content of propylene polymer (B) is less than the lower limit, the fluidity of the propylene resin composition will be insufficient, and the resulting molded article will tend to have poor rigidity. If it is more than the upper limit, the resulting molded article will tend to have reduced strength.

[0079] If the content of inorganic filler (D) is less than the lower limit, the resulting molded article tends to have inferior rigidity, and if it is more than the upper limit, the resulting molded article tends to have reduced strength.

[0080] In this invention, by using specific amounts of a propylene polymer (A) containing a high molecular weight propylene polymer component (A1), a low molecular weight propylene polymer (B), and an inorganic filler (D), it is presumed that a molded article with high rigidity and a low coefficient of thermal expansion can be obtained by promoting orientation by the propylene polymer component (A1) and promoting crystallization by the propylene polymer (B).

[0081] <Method for producing propylene resin compositions> The propylene resin composition of the present invention can be manufactured by blending the above-described components. The components may be blended sequentially in any order, or they may be mixed simultaneously. Alternatively, a multi-stage mixing method may be employed in which some components are mixed before others.

[0082] For example, a propylene-based resin composition can be produced by mixing a propylene-based polymer (A), a propylene-based polymer (B), an inorganic filler (D), and an optional component (e.g., an elastomer (C) or a nucleating agent) (D) as needed.

[0083] Methods for blending each component include, for example, using a mixing device such as a Banbury mixer, single-screw extruder, twin-screw extruder, or high-speed twin-screw extruder to mix or melt-knead each component simultaneously or sequentially. The resin temperature during melt-kneading is usually 180 to 280°C, preferably 180 to 260°C.

[0084] The composition of the present invention has a melt flow rate (MFR), measured at 230°C and a 2.16 kg load, preferably 1 to 300 g / 10 min, more preferably 3 to 250 g / 10 min, and even more preferably 5 to 120 g / 10 min. When the MFR is within the above range, the composition has an excellent balance between moldability and mechanical strength.

[0085] [Molded body] The molded article of the present invention is formed using at least the above-described composition of the present invention. The molded articles of the present invention can be suitably used in various fields, such as automotive parts, home appliance parts, food containers, and medical containers, and are particularly suitable as automotive parts. Examples of such automotive parts include automotive interior and exterior components such as bumpers, pillars, and instrument panels; automotive functional components such as engine fans and fan shrouds; and exterior panels such as roofs, door panels, and fenders.

[0086] The method for molding the molded article of the present invention is not particularly limited, and various methods known as methods for molding resin compositions can be used, but injection molding and press molding are particularly preferred. [Examples]

[0087] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0088] [Methods for measuring various physical properties] (1) Mass fraction: In the production of the propylene polymer (A-1) in Production Example 1, the mass fraction of the propylene polymer obtained in the first stage (first polymerizer) was determined from the amount of heat removed from the reaction heat generated during polymerization.

[0089] (2) Intrinsic viscosity [η]: The intrinsic viscosity [η] (dl / g) was measured at 135°C in tetralin solvent.

[0090] (3) Melt Flow Rate (MFR): The melt flow rate (MFR) (g / 10 min) was measured in accordance with JIS-K7210, at a measurement temperature of 230°C and a load of 2.16 kgf (21.2 N).

[0091] (4) Mesopentadione fraction (mmmm): The pentad fraction (mmmm,%), which is one indicator of the stereoregularity of polymers and represents their microtacticity, was assigned to propylene polymers based on Macromolecules 8,687 (1975). 13 It was calculated from the peak intensity ratio of the 1C-NMR spectrum. 13 The 1C-NMR spectrum was measured using a JEOL EX-400 instrument, with TMS as the reference, at a temperature of 130°C, and in o-dichlorobenzene solvent.

[0092] (5) Percentage of eluted components at temperatures below -20°C using the temperature-dependent elution fractionation method (TREF): The temperature-dependent elution fractionation method (TREF) was performed under the following measurement conditions, and the proportion of eluted components at temperatures below -20°C was calculated. Equipment: Polymer Char CFC2 cross-segment chromatograph Detector: Polymer Char IR4 infrared spectrophotometer (built-in) Mobile phase: o-dichlorobenzene, BHT added Flow rate: 1.0mL / min Sample concentration: 90 mg / 30 mL Injection volume: 0.5mL Melting conditions: 145℃, 30 minutes Stabilization conditions: 135℃, 30 minutes Cooling rate: 1.0℃ / min Dissolution range: -20℃ to 0℃ in 10℃ increments, 0℃ to 80℃ in 5℃ increments. 80℃~104℃ in 3℃ increments, 104℃~130℃ in 2℃ increments Dissolution time: 3 minutes

[0093] (6) Zirconium content in the prepolymerization catalyst component: The zirconium content in the prepolymerization catalyst components was measured using an ICP emission spectrometer (ICPS-8100) manufactured by Shimadzu Corporation. After wet decomposition of the samples with sulfuric acid and nitric acid, the samples were prepared in a fixed volume (including filtration and dilution as necessary) and quantified using a calibration curve created with standard samples of known concentration.

[0094] (7) Volume-based median diameter (D50), particle size distribution, and uniformity of the solid co-catalyst component: The volume-based median diameter (intermediate diameter, D50) and particle size distribution of the solid co-catalyst component were determined by laser diffraction and scattering using a Microtrac MT3300EX II from Microtrac. For particle size distribution measurements, samples of the solid co-catalyst component were pre-inactivated in a humid desiccator under nitrogen flow. Methanol was mainly used as the dispersion medium.

[0095] The uniformity of the solid co-catalyst component particles was evaluated using the uniformity index expressed by the following formula. Uniformity index = ΣXi|D50-Di| / D50ΣXi In the formula, Xi is the histogram value of particle i in particle size distribution measurement, D50 is the volume-based median diameter, and Di is the volume-based diameter of particle i. Xi, D50, and Di of the solid co-catalyst component particles were determined by the laser diffraction-scattering method described above.

[0096] (8) Flexural modulus (FM): The flexural modulus (FM) (MPa) was measured in accordance with JIS K7171 under the following conditions. Test specimen: 10mm (width) x 80mm (length) x 4mm (thickness) Bending speed: 2 mm / min Bending span: 64mm

[0097] (9) Coefficient of linear expansion (average): Coefficient of linear expansion (10 -5The thermal expansion coefficient (°C) was measured using the TMA method (measurement range: -30 to 80°C) in accordance with JIS K7197. Test specimens of approximately 10 mm × 5 mm × 2 mm thickness were cut from near the center of a small rectangular plate (30 mm (width) × 30 mm (length) × 2 mm (thickness)) in both the MD direction and the TD direction. After annealing the cut specimens at 120°C for 2 hours, the coefficient of linear expansion was measured for both the specimen cut in the MD direction and the specimen cut in the TD direction, and the average value of both was calculated.

[0098] The test specimens used to measure the flexural modulus and the coefficient of linear expansion (average) were prepared using the propylene-based resin compositions obtained in the examples or comparative examples, and manufactured in an injection molding machine under the following conditions.

[0099] (JIS small test specimens, small rectangular plates / injection molding conditions) Injection molding machine: "EC40" manufactured by Toshiba Machine Co., Ltd. Cylinder temperature: 190℃ Mold temperature: 40℃ Injection time - Holding time: 13 seconds (Primary filling time: 1 second) Cooling time: 15 seconds Unless otherwise specified, all examples were performed under a dry nitrogen atmosphere using a dry solvent.

[0100] [Manufacturing Example 1] (1) Preparation of solid titanium (a-1): After thoroughly purging a 2-liter high-speed stirring device (manufactured by Tokushu Kika Kogyo) with nitrogen, 700 ml of refined kerosene, 10 g of magnesium chloride, 24.2 g of ethanol, and 3 g of sorbitan distearate (Emazole 320, manufactured by Kao Atlas Co., Ltd.) were charged into the device. This system was heated under stirring and stirred at 120°C and 800 rpm for 30 minutes. Under high-speed stirring, the liquid was transferred using a 5 mm inner diameter Teflon® tube to a 2-liter glass flask (with a stirrer) filled with 1 liter of refined kerosene that had been pre-cooled to -10°C. The resulting solid was filtered and thoroughly washed with refined n-hexane to obtain a solid adduct in which 2.8 moles of ethanol were coordinated to 1 mole of magnesium chloride.

[0101] Next, the solid adduct (equivalent to 45 mmol of magnesium atoms) was suspended in 20 ml of decane, and then the entire amount was added to 195 ml of titanium tetrachloride, which was kept at -20°C, under stirring. This mixture was heated to 80°C over 5 hours, and 1.8 ml (6.2 mmol) of diisobutyl phthalate was added. The mixture was then heated to 110°C and stirred for 1.5 hours.

[0102] After the reaction was complete for 1.5 hours, the solid portion was collected by thermal filtration and washed with decane at 100°C and hexane at room temperature until titanium could no longer be detected in the filtrate. In this way, solid titanium (a-1) containing 3.8 wt% titanium, 16 wt% magnesium, 18.2 wt% diisobutyl phthalate, and 1.1 wt% ethanol residue was obtained.

[0103] (2) Preparation of solid titanium catalyst component (i-1): In a 200 ml glass reactor that had been thoroughly purged with nitrogen, 6.8 g of the obtained solid titanium(a-1), 113 ml of paraxylene, 11 ml of decane, 2.5 ml (23 mmol) of titanium tetrachloride, and 0.34 ml (1.2 mmol) of diisobutyl phthalate were added. The temperature in the reactor was raised to 130°C, and the mixture was stirred at that temperature for 1 hour for contact treatment. The solid portion was then collected by thermal filtration. This solid portion was resuspended in 101 ml of paraxylene, and then 1.7 ml (15 mmol) of titanium tetrachloride and 0.22 ml (0.8 mmol) of diisobutyl phthalate were added.

[0104] Next, the temperature was raised to 130°C, and the mixture was stirred for 1 hour while maintaining this temperature to allow the reaction to proceed. After the reaction was complete, solid-liquid separation was performed again by thermal filtration, and the obtained solid portion was washed with decane at 100°C and hexane at room temperature until the amount of paraxylene in the catalyst was 1% by weight or less. In this way, a solid titanium catalyst component (i-1) containing 1.3% by weight of titanium, 20% by weight of magnesium, 13.8% by weight of diisobutyl phthalate, and 0.8% by weight of diethyl phthalate was obtained.

[0105] The inventors speculate that the diethyl phthalate detected in the solid titanium catalyst component (i-1) is likely due to the transesterification of diisobutyl phthalate with the ethanol used to produce the solid titanium (a-1) during the manufacturing process of the solid titanium catalyst component.

[0106] (3) Preparation of prepolymerization catalyst (b-1): 100 g of the synthesized solid catalyst component (i-1), 34.2 mL of triethylaluminum, 36.7 mL of ethyldiethylaminodimethoxysilane, and 10 L of heptane were placed in a 20 L autoclave equipped with a stirrer. Maintaining an internal temperature of 15-20°C, 600 g of propylene was added, and the reaction was carried out for 120 minutes with stirring. After polymerization was complete, the solid components were allowed to settle, and the supernatant was removed and washed with heptane three times. The obtained prepolymerization catalyst was resuspended in purified heptane, and the concentration of the solid catalyst component was adjusted with heptane to 1.2 g / L. This prepolymerization catalyst (b-1) contained 6 g of polypropylene per gram.

[0107] (4) Production of propylene polymer (A-1): 300 L of propylene was charged into a 1000 L capacity vessel polymerizer equipped with a stirrer. While maintaining this liquid level, 117.1 kg / h of propylene, 1.5 g / h of prepolymerization catalyst (b-1) as a solid titanium catalyst component, 7.4 mL / h of triethylaluminum, and 3.6 mL / h of ethyldiethylaminodimethoxysilane were continuously supplied. Polymerization was carried out at a polymerization temperature of 74°C and under hydrogen barrier conditions at a pressure of 3.17 MPa / G.

[0108] The obtained slurry was sent to a second polymerizer, a vessel equipped with a stirrer with a capacity of 500 L, and further polymerization was carried out. In the second polymerizer, 300 L of propylene was charged, and while maintaining this liquid level, propylene was supplied at a rate of 10.1 kg / hour, and hydrogen was supplied so that the hydrogen concentration in the gas phase was 5.3 mol%. Polymerization was carried out at a temperature of 65.0°C and a pressure of 2.94 MPa / G.

[0109] The obtained slurry was sent to a third polymerizer, a vessel equipped with a stirrer with a capacity of 500 L, and further polymerization was carried out. In the third polymerizer, 250 L of propylene was charged, and while maintaining this liquid level, propylene was supplied at a rate of 10.0 kg / hour, and hydrogen was supplied so that the hydrogen concentration in the gas phase was 4.5 mol%. Polymerization was carried out at a temperature of 61.5°C and a pressure of 2.75 MPa / G.

[0110] The obtained slurry was transferred to a 1.9 L transfer tube, gasified, and subjected to a gas-solid separation operation to obtain a propylene polymer (A'-1). The obtained propylene polymer (A'-1) was vacuum dried at 80°C.

[0111] Furthermore, the slurry from the first polymerization reactor was withdrawn using a 1.6 L transfer tube, the slurry was gasified, and a gas-solid separation operation was performed. The intrinsic viscosity [η] of the resulting polypropylene powder was measured to be 11.5 dl / g.

[0112] Based on the amount of heat removed during polymerization, the proportion of the propylene polymer (A1) produced in the first polymerizer to the final obtained propylene polymer (A'-1) was 22% by mass.

[0113] To 100 parts by mass of propylene polymer (A'-1), 0.2 parts by mass of Irganox 1010 [manufactured by Ciba Specialty Chemicals Co., Ltd.] and 0.3 parts by mass of Irgaphos 168 [manufactured by Ciba Specialty Chemicals Co., Ltd.] were added as antioxidants, and 0.1 parts by mass of calcium stearate was added as a neutralizing agent. The mixture was then melt-kneaded in a twin-screw extruder to obtain pelletized propylene polymer (A-1). The physical properties of propylene polymer (A-1) are shown in Table 1.

[0114] [Table 1]

[0115] [Manufacturing Example 2] (1) Synthesis of transition metal complexes (metallocene compounds (M-1)): (8-octamethylfluoren-12'-yl-(2-(adamantan-1-yl)-8-methyl-3,3b,4,5,6,7,7a,8-octahydrocyclopenta[a]indene))zirconium dichloride (metallocene compound (M-1)) was synthesized according to Synthesis Example 4 of International Publication No. 2014 / 050817.

[0116] (2) Preparation of solid co-catalyst component (1): A solid polyaluminoxane composition, which is a solid co-catalyst component, was prepared based on a known method (the method described in International Publication No. 2014 / 123212). Specifically, 40 mL of toluene and a 20% by mass toluene solution of Albemarle polymethylaluminoxane (Al concentration = 2.95 mmol / mL, 166 mL, 490 mmol) were added to a 1 L glass autoclave equipped with a stirrer, and the temperature was raised to 45°C while stirring. Subsequently, a toluene solution of n-Octanophenone (14.7 g, 71.8 mmol) (20.5 mL) was added over 80 minutes. After addition, the mixture was stirred at 45°C for 30 minutes, and the temperature was raised to 115°C at a heating rate of 0.80°C / min, where the reaction was carried out for 30 minutes. Then, the temperature was raised to 150°C at a heating rate of 0.58°C / min, where the reaction was carried out for 150 minutes. After the reaction, the mixture was cooled to room temperature, and the resulting slurry was filtered. The powder on the filter was washed three times with dehydrated toluene. Then, dehydrated toluene was added to obtain a toluene slurry of the solid polyaluminoxane composition, which is the solid co-catalyst component (1). The particle size distribution of the obtained solid polyaluminoxane composition was measured. The volume-based median diameter (D50) was 9.8 μm, and the uniformity index was 0.237.

[0117] (3) Preparation of the solid catalyst component (metallocene catalyst) (1): In a 200 mL three-necked flask equipped with a stirrer and thoroughly purged with nitrogen, 17.8 mL of purified hexane and 20.5 mL of toluene slurry of the previously synthesized solid co-catalyst component (1) (2.00 g as solid content of the solid polyaluminoxane composition (solid co-catalyst component)) were charged under a nitrogen stream to form a suspension. The mixture was then heated to 35°C while stirring. Subsequently, 80.0 mg of the previously synthesized metallocene compound (M-1) (8.0 mL as a 10 mg / mL toluene solution) was added while stirring. After reacting for 60 minutes, 3.75 mL of toluene solution of triisobutylaluminum (1 mol / L in terms of aluminum atoms) was added and the mixture was reacted for another 60 minutes. After cooling to room temperature and stopping stirring, the supernatant (17 mL) was removed by decantation. The obtained solid catalyst component (1) was washed three times at room temperature with hexane (75 mL), and then hexane was added to prepare a total volume of 50 mL.

[0118] (4) Preparation of the prepolymerization catalyst component (BPP-1): To the slurry of the solid catalyst component (1) prepared as described above, 2.0 mL of a toluene solution of triisobutylaluminum (1 mol / L in terms of aluminum atoms) was added under a nitrogen stream. The mixture was then cooled to 20°C, and ethylene (6.3 g) was added over 6 hours. After the ethylene addition was complete, stirring was stopped, and decantation washing with hexane was performed at room temperature (washing efficiency 98%) to obtain 50 mL of hexane slurry. 10 mL of the obtained slurry was filtered, and the powder on the filter was washed twice with 10 mL of dehydrated hexane. The washed powder was dried under reduced pressure for 2 hours to obtain the prepolymerization catalyst component (BPP-1) as a powder. This was mixed with mineral oil to obtain a mineral oil slurry with a prepolymerization catalyst component concentration of 9.98% by mass. The zirconium content in the obtained prepolymerization catalyst component (BPP-1) was measured to be 0.087% by mass.

[0119] (5) Production of propylene polymer (B-1): A mixture of 160.0 mg of mineral oil slurry of the prepolymerization catalyst component (BPP-1) prepared as described above and 1.5 mL of decane solution of triethylaluminum (Al=0.5M) was charged into a 3.4 L SUS autoclave that had been thoroughly purged with nitrogen. Next, 750 g of liquid propylene and 13.1 L of hydrogen were charged, and polymerization was carried out at 70°C for 40 minutes with thorough stirring. The resulting polymer was dried under reduced pressure at 80°C for 10 hours to obtain 176.3 g of propylene polymer (B-1). The physical properties of propylene polymer (B-1) are shown in Table 2.

[0120] [Manufacturing Example 3] Production of propylene polymer (B-2): A mixture of 160.0 mg of mineral oil slurry of the prepolymerization catalyst component (BPP-1) prepared as described above and 1.5 mL of decane solution of triethylaluminum (Al=0.5M) was charged into a 3.4 L SUS autoclave that had been thoroughly purged with nitrogen. Next, 750 g of liquid propylene and 16.9 L of hydrogen were charged, and polymerization was carried out at 70°C for 40 minutes with thorough stirring. The resulting polymer was dried under reduced pressure at 80°C for 10 hours to obtain 179.7 g of propylene-based polymer (B-2). The physical properties of propylene-based polymer (B-2) are shown in Table 2.

[0121] [Manufacturing Example 4] Production of propylene polymer (B-3): A mixture of 160.0 mg of mineral oil slurry of the prepolymerization catalyst component (BPP-1) prepared as described above and 1.5 mL of decane solution of triethylaluminum (Al=0.5M) was charged into a 3.4 L SUS autoclave that had been thoroughly purged with nitrogen. Next, 750 g of liquid propylene and 9.2 L of hydrogen were charged, and polymerization was carried out at 70°C for 40 minutes with thorough stirring. The resulting polymer was dried under reduced pressure at 80°C for 10 hours to obtain 171.2 g of propylene-based polymer (B-3). The physical properties of propylene-based polymer (B-3) are shown in Table 2.

[0122] [Table 2]

[0123] [Example 1] 57.5 parts by mass of the propylene polymer (A-1) obtained in Production Example 1, 26.5 parts by mass of the propylene polymer (B-1) obtained in Production Example 2, 16 parts by mass of talc (D-1) ("HAR 3G77L", manufactured by Imerys Minerals Co., Ltd.), and additives (specifically, 0.1 parts by mass of the heat stabilizer "IRGANOX1010" (BSF Co., Ltd.), 0.1 parts by mass of the heat stabilizer "IRGAFOS168" (BSF Co., Ltd.), 0.1 parts by mass of calcium stearate, and 0.1 parts by mass of the antioxidant "H-BHT" (Honshu Chemical Industry Co., Ltd.)) were mixed in a tumbler. Then, the mixture was melt-kneaded in a twin-screw extruder under the following conditions to obtain a pelletized propylene resin composition. The physical properties of the propylene resin composition are shown in Table 3.

[0124] (Melting and mixing conditions) Co-directional twin-screw compounding extruder: "KZW-15" manufactured by Technovel Co., Ltd. Mixing temperature: 190℃ Screw rotation speed: 500 rpm Feeder rotation speed: 50 rpm

[0125] [Example 2] A propylene-based resin composition was obtained in the same manner as in Example 1, except that 0.2 parts by mass of a nucleating agent (E-1) ("HPN-20E," manufactured by Milliken Japan LLC) was added. The physical properties of the propylene-based resin composition are shown in Table 3.

[0126] [Example 3] A propylene-based resin composition was obtained in the same manner as in Example 1, except that the amount of propylene-based polymer (A-1) was changed to 38 parts by mass and the amount of propylene-based polymer (B-1) was changed to 46 parts by mass. The physical properties of the propylene-based resin composition are shown in Table 3.

[0127] [Example 4] A propylene resin composition was obtained in the same manner as in Example 1, except that 26.5 parts by mass of propylene polymer (B-1) was replaced with 26.5 parts by mass of propylene polymer (B-2). The physical properties of the propylene resin composition are shown in Table 3.

[0128] [Comparative Example 1] A propylene-based resin composition was obtained in the same manner as in Example 1, except that the amount of propylene-based polymer (A-1) was changed to 79 parts by mass and the amount of propylene-based polymer (B-1) was changed to 5 parts by mass. The physical properties of the propylene-based resin composition are shown in Table 3.

[0129] [Comparative Example 2] A propylene-based resin composition was obtained in the same manner as in Example 1, except that 26.5 parts by mass of propylene-based polymer (B-1) was replaced with 26.5 parts by mass of propylene-based polymer (B-3). The physical properties of the propylene-based resin composition are shown in Table 3.

[0130] [Table 3]

Claims

1. 30 to 80 parts by mass of a propylene polymer (A) that satisfies the following requirements (i) to (iii), 10 to 50 parts by mass of a propylene polymer (B) that satisfies the following requirements (iv) and (v), and Inorganic filler (D) in 1 to 20 parts by mass, and Optionally, 0 to 5 parts by mass of elastomer (C) (where the total amount of (A), (B), (C), and (D) is 100 parts by mass). A propylene-based resin composition containing this resin. (i) 5 to 25 parts by mass of a propylene polymer (A1) having an intrinsic viscosity [η] of 7 to 12 dl / g as measured at 135°C in a tetralin solvent, and a propylene polymer (A2) having an intrinsic viscosity [η] of less than 7 dl / g, The propylene polymer (A1) is a propylene homopolymer, The propylene polymer (A2) is selected from a propylene homopolymer and a copolymer (a) of propylene and an α-olefin having 2 to 20 carbon atoms (excluding propylene). In the copolymer (a), the content of constituent units derived from propylene is 93 mol% or more, and the content of constituent units derived from the α-olefin having 2 to 20 carbon atoms is 7 mol% or less, relative to the total number of constituent units derived from propylene and the total number of constituent units derived from the α-olefin having 2 to 20 carbon atoms. (ii) The melt flow rate (MFR) measured at 230°C and a 2.16 kg load is 1 to 20 g / 10 min. (iii) 13 The mesopentade fraction (mmmm) determined by C-NMR is 97.0–100%. (iv) The intrinsic viscosity [η] measured at 135°C in tetralin solvent is 0.15–0.28 dl / g. (v) Selected from a propylene homopolymer and a copolymer of propylene and an α-olefin having 2 to 20 carbon atoms (excluding propylene), wherein in copolymer (b), the content of constituent units derived from propylene is 98 mol% or more and less than 100 mol%, relative to the total number of constituent units derived from propylene and the number of constituent units derived from the α-olefin having 2 to 20 carbon atoms, and the content of constituent units derived from the α-olefin having 2 to 20 carbon atoms is greater than 0 mol% and 2 mol% or less.

2. The propylene polymer (B) 13 The propylene-based resin composition according to claim 1, wherein the mesopentade fraction (mmmm) determined by C-NMR is 90.0 to 100%.

3. The propylene-based resin composition according to claim 1 or 2, wherein the proportion of components that elute at a temperature of -20°C or lower by the temperature-dependent elution fractionation method (TREF) of the propylene-based polymer (B) is 3.5% by mass or less.

4. A propylene-based resin composition according to any one of claims 1 to 3, comprising 0.01 to 1 part by mass of a nucleating agent.

5. A molded article comprising the propylene resin composition according to any one of claims 1 to 4.

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